Can we wash out the magnetic particles from the cell surface using PBS?

We do not know if the magnetic nanoparticles left outside the cells could be removed during a PBS washing procedure.

Several PBS washes can remove some of them but we would suggest including one step of washing with an acidic buffer that could help to clean away the extracellular nanoparticles. In the applications reported so far, extracellular bound magnetic nanoparticles have not interfered with biological assays.